> In other words, while I agree with David C. that God is far more concerned
> with spiritual than physical attributes of his creatures--and his
> predestining may well not have included shapes of individual body
> parts--it's hard for me to imagine any form of marine life or invertebrate
> lifeÂ becoming capable of satisfyingÂ God's larger (presumed) requirement.
> (Well, maybe if dolphins had arms and hands with opposable thumbs....Â But
> how would they smelt ores under water?Â We can go into water and air and
> space; marine animalsÂ would have great difficulty doingÂ much of anythingÂ out
> of water.)

Just to clarify: I do think that the spiritual aspects are more
important, but did not mean to take a stand either way as to whether
the physical attributes are important.

Theologically, I think all the details were predestined and "what
might have been" may not be a meaningful question, but as far as I
know there's no scientific way to assess those points.

There are various studies that support the idea that only a certain
range of forms and lifestyles are available, and that almost all of
them have been taken by organisms, though of course it's hard to prove
without either a large sample of planets with complex life forms that
arose independently or else the ability to run an experiment for a
billion years or so.

Also, a lot of the features of interest here are very hard to quantify
and analyze. For example, Gould was quite excited about the fact
that, whereas almost all known post-Cambrian arthropods (and all known
post-Paleozoic ones) fit into a few categories based on the number,
position, and type of appendages (e.g., 0-2 pairs of antennae, which
segment has which mouthparts, 6 or 8 or more legs), many of the
Cambrian ones do not fit into these groups. On the other hand, most
of the Cambrian arthropods are vaguely shrimplike, such that Walcott
thought that they could fit into the standard groups and only with the
detailed study of the past four decades or so did the anomalies gain
attention. In contrast, anyone quickly can tell the differences
between a butterfly, a beetle, a bee, and a flea, yet they are all
members of a single major group of insects, the holometabolous orders.
If the insects had a breathing system that allowed them to get
bigger, they might have been able to develop large brains.

> And while Gould may have exaggerated the randomness of evolution, from what
> I know of it, and most emphatically in acknowledgement of the effects of
> mass extinctions, itÂ seems very likely that starting evolution at different
> times and places would lead to significantly different outcomes.Â While
> "changing one electron" should not have a major effect (unless it causedÂ a
> crucial mutation!), even a minor extinction event should have a noticeable
> effect.Â For example, such extinction is likely toÂ give some species a new
> competitive advantage that in turn mayÂ leadÂ it to eliminate still other
> species.
> Many authors have pointed out that more than 99% of all species have gone
> extinct.Â ChancesÂ seem very good that, under conditions of randomness and
> without any special guidance, theÂ species God wantedÂ would not have
> survived.
> Don

Of course, distinguishing special guidance from front-loading from
ordinary providence is not easy.

Although mass extinctions are notoriously "random" in being
unpredictable and not necessarily sparing apparently successful groups
(it's hard to think of any organismal feature short of advanced
technological culture that would help avoid an incoming asteroid, for
example), often certain characteristics do seem to convey an
advantage. Conway Morris's work on the topic is probably the most
extensive available, though of course taking a particular stance
rather than merely summarizing the pros and cons of all options.

A rather odd example comes from Dixon's envisioned world without a K/T
impact. Although he rejects Dale Russell's intelligent human-like
dinosauroid on ground that evolution is more random than that, a lot
of the things he does have look a whole lot like actual non-human
animals.

--
Dr. David Campbell
425 Scientific Collections
University of Alabama
"I think of my happy condition, surrounded by acres of clams"
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